What is the purpose of `__init_subclass__` in Python 3.6+?

Question

Python Professional — Hard

What is the purpose of `__init_subclass__` in Python 3.6+?

Accepted Answer

`__init_subclass__` in Python 3.6+ is called on the base class whenever it is subclassed, allowing customization for subclasses. This method is not a replacement for `__init__` and does not prevent further subclassing.